Early-onset bipolar disorder poses a major health risk to affected individuals. Adolescents with DSM-IV bipolar I disorder are at high risk for hospitalizations, social and academic deterioration, suicide, substance abuse, and pharmacological nonadherence. Treatment research for bipolar adolescents has lagged behind research for adults, particularly in the psychosocial arena. A promising psychosocial model is family-focused treatment (FFT), consisting of psychoeducation for the patient and relatives about bipolar disorder, communication enhancement training, and problem-solving training. In two randomized trials, FFT was found to be an efficacious adjunct to pharmacotherapy in the 2-year course of adult bipolar I disorder. We propose developing and standardizing a version of FFT that is attuned to the developmental needs of adolescent bipolar I patients, and testing its efficacy with pharmacotherapy at two centers of expertise in adult and pediatric-onset bipolar disorders: the Univ. of Colorado and the Univ. of Pittsburgh Medical Center. In Phase I (Colorado only), 12 bipolar I adolescents and parents will participate in an open trial of 9-month FF1, delivered according to a preliminary adolescent-focused manual (FFT-A) developed in feasibility testing. The adolescents will be treated with pharmacotherapy using a clinical management manual. Based on Phase 1, we will modify the FF1-A manual to maximize its developmental sensitivity and engagement of adolescents, and standardize therapist adherence and competence scales. In Phase 2 (Colorado), we will further revise and streamline the FF1-A model through incorporating the feedback of Phase I adolescents and parents, therapists, and psychiatrists. In Phase 3 (Colorado and Pittsburgh), we will conduct a pilot randomized trial (N = 50) of the streamlined FF1-A plus pharmacotherapy (n = 25) versus treatment-as-usual (TAU; an educational self-help workbook) plus pharmacotherapy (n = 25). Raters who are unaware of treatment assignments will assess patients' outcomes at baseline, 3, 6, 9, and 12 months. We hypothesize that FFT-A will be superior to TAU in improving adolescents' symptom trajectories, social/school functioning, and adherence to medication, and decreasing their need for ancillary health services. Secondary analyses will examine the impact of FFT-A on parents' mood states and subjective distress, and on other hypothesized mediating mechanisms: family expressed emotion, family interactional behavior, and social rhythm stability.